Underlayment membrane



FIG. 1 is a top perspective view of an underlayment membrane incorporating the design.

FIG. 2 is an enlarged view of encircled area 2 of FIG. 1.

FIG. 3 is an enlarged perspective cross-sectional view along 3-3 of FIG. 1.

FIG. 4 is an enlarged view of encircled area 4 of FIG. 1.

FIG. 5 is a bottom perspective view of the underlayment membrane; and,

FIG. 6 is an enlarged perspective cross-sectional view along 6-6 of FIG. 1. 

CLAIM The ornamental design for an underlayment membrane, as shown and described. 